This undated photo courtesy of the National Park Service shows Harding Icefield in Alaska's Kenai Fjords National Park. The National Park Service considers the 7.4-mile round-trip hike strenuous, ... more 
This undated photo courtesy of the National Park Service shows Harding Icefield in Alaska's Kenai Fjords National Park. The National Park Service considers the 7.4-mile round-trip hike strenuous, saying hikers gain about 1,000 feet of elevation with each mile. less 
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Associated Press | Photo By National Park Service
Thu, Mar 24, 2011 8:07 PM EDT